Dehydrogenation and dehydrocyclization catalyst

ABSTRACT

Non-acid microporous crystalline indium containing materials are combined with Group VIII metal such as platinum to produce catalysts which exhibit high selectivity for dehydrocyclization of C 5   +   paraffins and which exhibit little, if any, cracking activity for hexane and heptane.

FIELD OF THE INVENTION

Non-acidic catalysts based on crystalline microporous materialscontaining a dehydrogenation metal and a modifier comprising indium aredescribed. The compositions exhibit high selectivity in the catalyticdehydrogenation and/or dehydrocyclization of paraffins.

BACKGROUND OF THE INVENTION

Naturally occurring and synthetic crystalline microporous materials havebeen demonstrated to exhibit catalytic properties for various types ofhydrocarbon conversions. The term "crystalline" used to refer to thesematerials relates to the ordered definite crystalline structure of thematerial which is unique and thus identifiable by a characteristic X-raydiffraction pattern.

The term "microporous" as it refers to such material relates to pores,or channels, with diameters of less than 20 Angstroms. Examples of thesemicroporous crystalline materials include crystalline silicates,crystalline alumino-silicates (zeolites), crystalline ALPOs, crystallineSAPO and related compositions and intercalated pillared materialsderived from clays, layered silicates and titanates. The crystallinesilicate, alumino silicate (zeolites), ALPOs and SAPOs, have pores ofuniform size and channel systems which are uniquely determined by unitstructure of the material. The uniform pore size and/or channel systemsallow such a material to selectively absorb molecules of certaindimensions and shapes. In the art, microporous material having pores, orchannels, of less than 20 Angstroms, can be divided into small, mediumand large pore by the diameters of those pores, or channels. The poresof the small pore material have an average diameter of less than 5Angstroms; medium size pores range from an average diameter of about 5to about 7 Angstroms, and large pore materials indicates a diameter ofgreater than about 7. The word "average" is used to refer to diameter toembrace those species in which the pore is elliptical. Alternatively,the demarcation between small, medium, and large pore materials can bebased on the following sorption properties (measured at room temperaturefor crystallites having a minimum dimension of 0.1 micron):

1. Small pore: n-C₆ /i-C₆ sorption ratio greater than approximately 10.

2. Medium pore: n-C/hd 6/i-C₆ is less than 10 and n-C₆ /Mesitylenesorption ratio greater than approximately 5.

3. Large pore: n-C₆ /Mesitylene sorption ratio less than approximately5.

In the art, zeolites are a subclass of crystalline microporoussilicates. Zeolites can contain aluminum as well as silicon. In somezeolites, the upper limit of the silicon/aluminum atomic ratio isunbounded. ZSM-5 is one such example wherein the silicon/aluminum atomicratio is at least 2.5 and up to infinity. By way of illustration, U.S.Pat. No. 3,941,871, reissued as RE 29,948, discloses a porouscrystalline silicate made from a reaction mixture containing nodeliberately added aluminum and exhibiting the X-ray diffraction patterncharacteristic of ZSM-5 zeolites.

Zeolites can be acidic or non-acidic, depending on the frameworkaluminum content and on the amount of compensating cations, such as Na⁺,K⁺, etc. ALPOs described in U.S. Pat. No. 4,310,440, which isincorporated by reference herein, are neutral. SAPOs described forexample in U.S. Pat. No. 4,440,871, which is incorporated by referenceherein, can be acidic or non-acidic depending on the ratio of frameworkAl:P therein and the compensating cation, such as Na⁺, K⁺ (other thanproton species and other than proton forming species such as NH₄ ⁺).ELAPOs are described in U.S. Pat. No. 4,500,651, while MeAPOs aredescribed in U.S. Pat. Nos. 4,544,143 and 4,567,029, each of said latterthree patents being incorporated by reference herein.

SUMMARY OF THE INVENTION

The present invention is directed to a new composition of matter, to itsmethod of production, and to its use as a catalyst in paraffindehydrogenation and paraffin dehydrocyclization. The composition is anon-acidic, microporous crystalline material containing adehydrogenating metal and a modifier, indium. It has been discoveredthat these non-acidic crystalline microporous indium containingmaterials containing a dehydrogenation metal exhibit high selectivityfor dehydrogenation and/or dehydrocyclization of paraffins. Moreover,while exhibiting that high selectivity for paraffin dehydrocyclization,these compositions exhibit decreased selectivity for hydrogenolysis(especially methane formation) relative to their indium-freecounterparts.

DESCRIPTION OF THE DRAWINGS

FIG. 1 is an X-ray diffraction pattern of In-ZSM-5 produced in Run No. 8of Example 1.

FIG. 2 is an X-ray diffraction pattern of In-ZSM-12 produced in Run. No.13 of Example 1.

FIG. 3 is an X-ray diffraction pattern of In-ZSM-48 produced in Run No.6 of Example 1.

DETAILED DESCRIPTION OF THE INVENTION

One aspect of the invention is a catalyst comprisinghydrogenation/dehydrogenation metal and a non-acidic crystallinemicroporous indium containing material. As catalysts these non-acidicforms of compositions exhibit extremely high selectivity for paraffindehydrogenation and/or dehydrocyclization reactions, under conditionseffective for paraffin dehydrogenation and/or aromatization.

The amount of dehydrogenation metal in the catalyst can range from 0.01to 30 weight percent and preferably 0.1 to 10 weight percent of thecrystalline indium containing material. In a preferred embodiment,platinum is the hydrogenation/dehydrogenation metal. However, thehydrogenation/dehydrogenation metal can be any Group VIII metalincluding those of the platinum group, chromium and vanadium.

The indium content of the crystalline materials can range from 0.01 to20 weight percent. Practically, the indium content will range from 0.1to 10 weight percent.

The crystalline indium containing materials of the invention includezeolites characterized by Si/Al ratios of at least 2. However, thesilica:alumina ratio can be up to 1000, or greater. In specificembodiments the aluminum content of some of these materials is less than0.1 weight percent. The crystalline indium containing silicate materialofthe invention can contain other elements including boron, iron,chromium and gallium. The content of these other elements in thecrystalline indiumcontaining silicates can range from 0 to 10 weightpercent.

The indium containing precursors of the invention, described herein, arecrystalline in the sense that they are identifiable as isostructuralwith known crystalline materials by X-ray powder diffraction pattern.

The crystalline microporous indium containing material has an X-raydiffraction pattern which corresponds to a zeolite, SAPO, ALPO, etc. Forexample, indium compositions of the invention have been made the crystalstructure of which is that of ZSM-5, ZSM-11, ZSM-12 ZSM-23, ZSM-48,ZSM-50, zeolite Beta, ZSM-20, SAPO-5 ALPO-5. These are characterized bypore sizes up to about 8 Angstroms. The X-ray diffraction pattern andsignificant lines Tables of these materials have been described in theU.S. Patent literature. In a preferred embodiment the pore size of themicroporous crystalline indium containing materials ranges from about 5toabout 8 Angstroms.

The compositions comprising hydrogenation/dehydrogenation metal combinedwith the crystalline indium containing microporous crystalline materialsdo not exhibit any appreciable acid activity. These catalysts would meetthe criteria of non-acidic catalysts described by Davis and Venuto, J.CATAL. Vol. 15, p. 363 (1969). Thus, a non-equilibrium mixture ofxylenes are formed from either n-octane or each individual methylheptaneisomer, with the n-octane yielding more o-xylene and 2-methyl-heptaneyielding mostly m-xylene, at conversions between and 10 and 60%.Alternatively, thenon-acidic compositions will exhibit a pH of at least6 when added to distilled deionized pH7 water maintained under inert(such as argon) atmosphere; by an inert atmosphere in this context itmeans an atmosphere free of CO_(2`). Typically, in these tests, 100 mgof catalyst was addedto 30 ml. of distilled deionized water. Somecompositions will exhibit a pHof at least 7.5.

When, as in embodiments herein, the crystalline indium dehydrogenationmetal containing material exhibits an X-ray diffraction pattern of azeolite, at least some of the dehydrogenation metal may beintrazeolitic, that is, some of that metal is within the pore structureof the crystal, although some of that metal can be on the surface of thecrystal. A test for determining whether, for example, Pt isintrazeolitic or extrazeoliticin the case of ZSM-5 is reported by R. M.Dessau, J. CATAL. Vol. 89, p. 520(1984). The test is based on theselective hydrogenation of olefins.

Compositions of the invention used in catalysis decrease the hydrogencontent of the reactant to produce a product having the same number ofcarbon atoms as the number of carbon atoms in the reactant. Bycomparison indium-free counterparts of those compositions catalyzed alsohydrogenolysis of paraffins, e.g., to methane, as a major competing sidereaction; and, accordingly, the latter compositions exhibit decreasedselectivity for the aromatization of paraffins but increased selectivityfor C₁ -C₅ paraffin production. Some of the aforementioned catalystswere screened for hexane and heptane aromatization at 538° C. in thepresence of nitrogen diluent. The results are shown in Table A below inwhich the crystalline microporous indium containing material employedexhibited the diffraction pattern of a ZSM-5.

                  TABLE A                                                         ______________________________________                                        Paraffin Aromatization over Pt/ZSM-5                                                            Con-    Benz.                                               Support  Paraffin version Sel.(c)                                                                             Tol. Sel.                                                                            C5-Sel.                                ______________________________________                                        B/ZSM-5  n-hexane 52%     31%   --     12%  (a)                               "        "        98%     51%   2%     40%  (a)                               "        heptane  56%     56%   8%     7%   (a)                               "        "        95%     33%   31%    34%  (a)                               In/ZSM-5 n-hexane 60%     81%   --     1%                                     "        "        99+%    95%   --     4%                                     "        heptane  50%     --    92%    1%                                     "        "        99%     --    97%    1%                                     Si/ZSM-5 (b)                                                                           n-hexane 58%     69%   --     18%  (a)                               "        "        99%     72%   --     26%  (a)                               "        heptane  34%     45%   17%    14%  (a)                               "        "        99%     62%   4%     34%  (a)                               ______________________________________                                        (a) primarily methane.                                                        (b) high silica/alumina ZSM5.                                                 (c) H.sub.2 --free selectivity based on carbon                            

The non-acidic platinum catalyst prepared from In/ZSM-5 provided muchhigher aromatics selectivity than all the other catalysts examined.Benzene yields from hexane were as high as 95%, while heptane producedtoluene in 97% yield (H₂ free carbon base).

By comparison, other non-acidic platinum/high silica ZSM-5 catalystscontaining the elements Cr, Ti, Sc, Ni, Au, Ge, Zr, all produced toluenein less than 55% yield from n-heptane. In contrast, theindium-containing catalyst gave better than 95% yield (on carbon basis).

The other catalysts, including Pt/B-ZSM-5 and Pt/high silica:aluminaratio ZSM-5 as well as those others enumerated above did not show anyappreciable acid activity, in that platinum chemistry dominated.Significant metal-catalyzed aromatization was observed; howeverhydrogenolysis to methane constituted a major competing side reaction.Thehighest toluene selectivity from n-heptane observed was 50-55%, andin mostcases that selectivity was significantly lower. This is in sharpcontrast to the aromatic product selectivity of the platinum/In/ZSM-5.The cause for this difference in platinum behavior from the Pt/In-ZSM-5catalyst is not clear.

SYNTHESIS OF THE COMPOSITIONS

The crystalline indium-materials can be made in various ways. Indiumincorporation can be during synthesis or post-synthesis; and thematerialscan be prepared either by stepwise or simultaneousincorporation of the indium and the hydrogenation/dehydrogenationfunction to the crystallization reaction product. The dehydrogenationfunction can be first introduced to the synthesis product withsubsequent indium incorporation, or vice versa. Stepwise preparationincludes techniques of cocrystallization, impregnation, or exchange.Crystallization with indium can be undertaken in a two phase systemdescribed in commonly assigned Ser. No. 878,555, filed June 26, 1986.Other elements such as boron, iron,chromium, gallium, can also beincluded. Simultaneous incorporation includes the combination of indiumwith the dehydrogenation/hydrogenation function during synthesis (i.e.,crystallization) or simultaneously after synthesis of the crystallinematerial.

An indium free material can be treated with indium compounds at elevatedtemperatures. Such treatments can be conducted so that the source ofindium is either in the gaseous (such as indium chloride) or the liquidphase including the aqueous phase (such as indium nitrate).Alternatively,an indium free crystalline reactant can simply beimpregnated with indium source and then calcined at temperatures above400° C.

The indium free reactant may have high silica:alumina ratios or containother elements such as boron, chromium, iron, and gallium. Reactants andproducts containing 0.1 weight percent or less aluminum are thepreferred embodiments of the examples. In materials of the invention,all cation-exchangeable sites are occupied by cations other thanhydrogen and other than hydrogen precursors, such as NH₄ ⁺.Specifically, suchsites are occupied by Na⁺, K⁺, Cs⁺, Ca⁺, Mg⁺⁺, Ba⁺⁺,Sr⁺⁺, or admixtures thereof. The alkali metals served to neutralize anyacidity due to framework aluminum. The source of alkali metal cation canderive from cations incorporated during synthesis, in excess of thealuminum content thereof. Alternatively, one can treat the final productwith a basic solution of an alkali metal hydroxide as a final step priorto use, as described for example in U.S. Pat. No. 4,652,360.

The non-acidic, crystalline, microporous, indium modifier anddehydrogenation metal containing materials of the invention can becombined with a matrix or binder material to render them attritionresistant and more resistant to the severity of the conditions to whichthey will be exposed during use in hydrocarbon conversion applications.The combined compositions can contain 1 to 99 weight percent of thematerials of the invention based on the combined weight of the matrix(binder) and material of the invention. When used in dehydrogenationand/or dehydrocyclization, the material of the invention will preferablybe combined with non-acidic matrix or binder materials. A preferredmatrixor binder material would be silica, when the materials of theinvention areused in dehydrogenation/hydrogenation ordehydrocyclization.

These compositions of the invention exhibit high selectivity fordehydrogenation and/or dehydrocyclization, which is evidenced by thefollowing examples. In the following examples paraffins of at least twocarbon atoms are contacted with compositions of the invention at 0.1 to500 psig, 550° to 1300° F., LHSV of 0.1 to 20, and reactor inlet H₂/reactant (paraffin) ratios of 5 or less; preferably when the paraffinis C₅ ⁴, the temperature is at least 720° F. Furthermore, thecompositions of the invention have found application in the productionof olefins as described in concurrently filed patent application Ser.No., (MOBIL DKT. 4397); in upgrading naphthas by reforming as describedin concurrently filed patent application Ser. Nos.,(MOBIL DKT 4400);and, (MOBIL DKT. 4398) in a one-step transformation of octane withselective styrene production as described in concurrently filed patentapplication Ser. No., (MOBIL DKT. 4369); in post reforming ofparaffinrich reformates, as described in concurrently filed patent applicationSer. No., (MOBIL DKT 4374); and in dewaxing as described in concurrentlyfiled patent application Serial No., (MOBIL DKT. 4399).

EXAMPLES Example 1

Crystalline silicate products were produced containing indium andexhibiting characteristic X-ray diffraction patterns of structurescorresponding to ZSM-5, ZSM-11, ZSM-12, ZSM-23, ZSM-48 and ZSM-50.

Table 1 compiles the composition ranges employed in the synthesis of aseries of In/ZSM-5 products with widely varying indium content. Alsoshownin Table 1A is the synthesis of indium-containing silicates havingX-ray pattern of ZSM-11, ZSM-12, ZSM-23, ZSM-48 and ZSM-50. Thefootnotes in Table 1A specify the SiO₂ sources and the organic directingagents employed in the synthesis.

                                      TABLE 1A                                    __________________________________________________________________________    Crystallizations of Indium-Containing Zeolites                                160° C.; Stirred 400 rpm                                               Mixture Composition (Mole Ratios)                                              Run No.                                                                            ##STR1##                                                                           ##STR2##                                                                           ##STR3##                                                                           ##STR4##                                                                           ##STR5##                                                                           Time, Days                                                                          Zeolite Product                          __________________________________________________________________________     1.sup.a                                                                           500  48   0.26 0.27 0.10.sup.c                                                                         3     ZSM-5                                      2.sup.b                                                                           500  48   0.26 0.27 0.10.sup.c                                                                         3     ZSM-5                                      3.sup.a                                                                           300  48   0.26 0.28 0.10.sup.c                                                                         3     ZSM-5                                      4.sup.b                                                                           300  48   0.26 0.28 0.10.sup.c                                                                         1     ZSM-5                                      5.sup.d                                                                           300  48   0.26 0.28 0.20.sup.b                                                                         1     ZSM-5                                      6.sup.b                                                                           200  48   0.26 0.30 0.10.sup.e                                                                         4      ZSM-48                                    7.sup.b                                                                           200  48   0.26 0.30 0.10.sup.f                                                                         4      ZSM-11                                    8.sup.b                                                                           150  48   0.26 0.31 0.10.sup.c                                                                         2     ZSM-5                                      9.sup.b                                                                           150  48   0.26 0.31 0.10.sup.c                                                                         2     ZSM-5                                     10.sup.b                                                                           150  48   0.26 0.31 0.10.sup.c                                                                         2     ZSM-5                                     11.sup.b                                                                           150  48   0.26 0.31 0.10.sup.c                                                                         3     ZSM-5                                     12.sup.b                                                                           150  48   0.26 0.31 0.10.sup.c                                                                         2     ZSM-5                                     13.sup.b                                                                           100  48   0.26 0.34 0.08.sup.g                                                                         3      ZSM-12                                   14.sup.h                                                                            76  48   0.26 0.59 0.10.sup.c                                                                         6     ZSM-5                                     15.sup.i                                                                            70  40   0.20 0.23 0.10.sup.c                                                                         3     ZSM-5                                     16.sup.b                                                                            70  40   0.26 0.37 0.10.sup.c                                                                         3     ZSM-5                                     17.sup.a                                                                            60  48   0.26 0.39 0.10.sup.c                                                                         3     ZSM-5                                     18.sup.b                                                                           150  40   0.20 0.25 0.10.sup.j                                                                         3      ZSM-23                                   19.sup.b                                                                           300  40   0.20 0.23 0.10.sup.j                                                                         3      ZSM-23                                   20.sup.b                                                                           300  40   0.20 0.23 0.10.sup.k                                                                         3      ZSM-50                                   __________________________________________________________________________     .sup.a Silica source is tetraethylorthosilicate (Et.sub.4 SiO.sub.4)          .sup.b Silica source is SPEX Industries precipitated SiO.sub.2                .sup.c R = TPA+-                                                              .sup.d Silica source is DeGussa fumed SiO.sub.2                               ##STR6##                                                                      .sup.f R = TBA+-                                                              ##STR7##                                                                      .sup.h Q-brand sodium silicate                                                .sup.i Silica source is kieselsaure precipitated SiO.sub.2                    ##STR8##                                                                      .sup.k R = Dibenzyldimethylammonium ion                                  

Table 2A is a compilation of chemical analyses of some of ourindium-containing products. These products vary in indium content from0.36-5.20 wt % In. The formulas of the zeolite products are expressed inTable 2 as a ratio of oxides per mole of In₂ O₃.

                                      TABLE 2A                                    __________________________________________________________________________    Analyses of Some Indium-Containing Zeolitic Silicate Products                 Sample Run from No.                                                                  Weight Percent CNNaInSiO.sub.2Al.sub.2 O.sub.3Ash                                                    ##STR9##                                                                           Moles per Mole In.sub.2 O.sub.3                                               N.sub.2 ONa.sub.2 OAl.sub.2 O.sub.3SiO.                                       sub.2                                      __________________________________________________________________________    15     6.96                                                                             0.66                                                                             3.28                                                                             5.20                                                                             62.47                                                                            0.070                                                                             85.34                                                                            12.3   1.04                                                                            3.15                                                                              0.03                                                                               46                             14     6.74                                                                             0.43                                                                             2.64                                                                             4.19                                                                             69.94                                                                            0.24                                                                              86.20                                                                            18.3   0.84                                                                            3.14                                                                              0.13                                                                               64                             16     7.02                                                                             0.56                                                                             0.79                                                                             3.48                                                                             76.45                                                                            0.035                                                                             84.78                                                                            14.6   1.32                                                                            1.13                                                                              0.02                                                                               84                             13     6.01                                                                             0.61                                                                             0.65                                                                             2.79                                                                             81.83                                                                            0.031                                                                             91.79                                                                            11.2   1.79                                                                            1.16                                                                              0.025                                                                             112                              9     8.02                                                                             0.71                                                                             0.98                                                                             2.11                                                                             74.85                                                                            0.078                                                                             88.05                                                                            13.6   2.36                                                                            2.29                                                                              0.06                                                                              132                              8     8.01                                                                             0.68                                                                             1.48                                                                             2.14                                                                             74.64                                                                            0.11                                                                              88.72                                                                            13.7   2.61                                                                            3.45                                                                              0.11                                                                              133                             12     7.93                                                                             0.74                                                                             2.56                                                                             2.26                                                                             83.85                                                                            0.005                                                                             88.05                                                                            12.4   2.68                                                                            1.23                                                                              0.009                                                                             142                             10     8.37                                                                             0.81                                                                             1.83                                                                             1.92                                                                             73.14                                                                            0.025                                                                             88.36                                                                            12.0   3.46                                                                            4.76                                                                              0.03                                                                              146                             11     8.22                                                                             0.62                                                                             0.54                                                                             1.49                                                                             82.14                                                                            0.031                                                                             85.96                                                                            15.5   3.41                                                                            1.81                                                                              0.05                                                                              211                              6     4.58                                                                             0.79                                                                             0.48                                                                             1.46                                                                             86.70                                                                            0.029                                                                             91.86                                                                            6.7    4.44                                                                            1.64                                                                              0.045                                                                             227                              7     8.66                                                                             0.51                                                                             0.44                                                                             0.96                                                                             82.29                                                                            0.013                                                                             89.43                                                                            19.8   4.36                                                                            2.29                                                                              0.045                                                                             328                              2     8.12                                                                             0.69                                                                             0.40                                                                             0.36                                                                             78.05                                                                            0.083                                                                             85.69                                                                            13.7  15.7                                                                             5.55                                                                              0.52                                                                              830                             __________________________________________________________________________

X-ray powder diffraction patterns of typical In-containing zeoliteproductsare in the Figures of the Drawings. FIG. 1 is the diffractionpattern for In/ZSM-5 (Sample of Run No. 8), FIG. 2 is the diffractionpattern for In/ZSM-12 (Sample from Run No. 13) and FIG. 3 is the patternfor In/ZSM-48(Sample from Run No. 6).

Example 2

The In/ZSM-5 of that run No. 12 was prepared as follows:

The source of the indium can be incorporated into the zeolitic silicatesynthesis reaction mixture as a partial, or preferably as a completesubstitute for sources of alumina (or boron) conventially used inzeolite synthesis. In the embodiments described below the crystallineindium containing silicates were synthesized from crystallizationreaction mixtures which contained no deliberately added sources of Al₂O₃.

A commercial silica gel (SPEX Ind.) with very low aluminum contaminationwas employed in the synthesis of In-ZSM-5. First, 0.85 g In(NO₃)₃ and2.66 g NaOH pellets were dissolved in 180.2 de-ionized water, then 5.64g tetrapropylammonium bromide (TPABr) was dissolved in this basicsolution. This solution was transferred to a 300 ml stainless steelautoclave, and 15.0 g of silica gel (SPEX) was added. The autoclave wasthen sealed and stirring and heating was begun. The hydrogel formed bythis reaction mixture is described by the following mole ratios:

    ______________________________________                                               SiO.sub.2 /In.sub.2 O.sub.3                                                           150                                                                   H.sub.2 O/SiO.sub.2                                                                   48                                                                    OH.sup.- /SiO.sub.2                                                                   0.26                                                                  Na.sup.+ /SiO.sub.2                                                                   0.31                                                                  TPA.sup.+ /SiO.sub.                                                                   0.10                                                           ______________________________________                                    

The hydrogel was reacted at 160° C. for 2 days at a stirring rate of400rpm before quenching. The resultant crystalline product was filtered,washed, and dried. X-ray powder diffraction analysis showed the producttobe 100% crystalline ZSM-5, when compared to the diffraction pattern ofa conventional ZSM-5. Elemental analysis of the ZSM-5 product gave:C=7.93 wgt %, N=0.74%, Na=0.56%, In=2.26%, Al 0.005%, SiO₂ =83.85%,Ash=88.05%.

These results expressed in mole ratios were: C/N=12.5; Moles/mole In₂ O₃: N₂ O=2.68, Na₂ O=1.23, Al₂ O₃ =0.009, SiO₂ =142.

Platinum incorporation was undertaken as follows: The as-synthesizedzeolite was heated in nitrogen to 520° C. at lC/min and held there for 6hours. It was then calcined in air in a similar manner. Thecalcinedzeolite analyzed for 41.05% Si, 2.21% In (Si/In2=152), and 120ppm Al, and sorbed 10.4% n-hexane at 90° C. The calcined zeolite (3 g)was stirred in a solution of 150 mg Pt(NH₃)₄ Cl₂ in 100 ml water at roomtemperature overnight. After being washed, filtered and dried, theion-exchanged zeolite was found to contain 0.41 meq NH₃ /gash, which isequivalent to 1.89% Pt on sample. The platinum tetramine zeolite wasthen calcined in oxygen to 350° C. at 0.5C/min and heldthere for 1 hour.Elemental analysis indicated the presence of 1.85% Pt on the finalcatalyst.

At very high hexane conversions (99%), benzene was formed in over 94%yield. Similarly, n-heptane yielded 96% toluene. Similarly, n-heptaneyielded 96% toluene. Consistent with the non-acidic nature of thisplatinum catalyst, n-octane yielded predominately ethylbenzene andortho-xylene, 2-methylheptane produced mostly meta-xylene, and3-methylheptane formed mainly ethylbenzene, para-, and ortho-xylene.

Example 3

In EXAMPLE 1, zeolitic silicate was made using In(NO₃)₃ in thecrystallization reaction mixture. In the Example below, indium wasincorporated post-synthesis; in a subsequent step platinum wasion-exchanged onto the zeolite.

In this example, a high silica/alumina (10,000) ZSM-11 was calcined innitrogen and then in air at 538° C. InCl₃ vapors were passed through thezeolite in a stream of nitrogen, while it was heated to 500° C. at10C/min. The zeolite was maintained at 500° C. for 1.5 hours. Aftercooling, the catalyst was added to 200 ml 1M NH₄Cl adjusted to pH 9.5with NH₄ OH. The mixture was stirred for 20 minutes at room temperature,and then filtered. The zeolite was then reexchanged for 3 hours with 1MNH₄ Cl adjusted to pH 7.6. Thermogravimetric analysis indicated thepresence of 0.325 meg/g ammonium ion in the zeolite.

Platinum was incorporated by ion exchange with Pt(NH₃)₄ Cl₂ at roomtemperature. The platinum zeolite was then calcined in oxygen to 350° C.at 0.5C/min.

Under aromatization conditions, the catalyst effected aromatization ofn-heptane to toluene in high yield. At about 500° C. (up to about 538°C.) and 30 torr heptane in nitrogen, toluene was formed in94%selectivity at a conversion level of greater than 90%.

Example 4

The ZSM-5-type borosilicate was synthesized at 170° C. from a mixture of12.4 g high purity silica (SPEX), 105 g 20% TEA hydroxide, and 0.8 gboric acid. The as-synthesized zeolite was then calcined in nitrogenandthen in air at 520° C. The calcined zeolite contained 41.39% Si,0.015%Al, and 0.44% B.

Two grams of the calcined borosilicate was impregnated with 135 mgIn(NO₃)₃, all calcined in air at 500° C. for 2 hours. 1.8g of thismaterial was then ion-exchanged with 28 mg Pt(NH₃)₄ Cl₂ in 100 ml waterat room temperature. TGA analysis in hydrogen indicated the presence of0.18. meq N/g equivalent to 0.87% Pt. The platinum-exchanged zeolite wasthen calcined in oxygen to 350° C. at 0.5° C./min.

The catalyst activity of the foregoing composition was examined. The"non-acidic" nature of the catalyst was confirmed by its ability toaromatize n-heptane to toluene in high yield. At 500° C. and 30 torrheptane in nitrogen, toluene was formed in 95% yield. Furthermore, thesmall amounts of both methane and propane produced were exceeded by theethane formed, indicative of the low hydrogenolysis and acid activity ofthe catalyst.

    ______________________________________                                                                            % Toluene                                 % Conversion                                                                            % Cl     % C2    % Benzene                                                                              (Selectivity)                             ______________________________________                                        96        0.4      0.6     1.3      92 (96%)                                  99        0.5      1.0     1.5      95 (96%)                                  ______________________________________                                    

Example 5

Indium-containing zeolite ZSM-20 was synthesized by the followingprocedure:

12.75 grams of sodium aluminate (NaAlO₂) and 6.02 grams indiumnitratewere dissolved in 57.96 grams of deionized water. After the solidingredients dissolved, 484.1 ml of 2.88N tetraethylammonium hydroxide(TEAOH) was added to the solution. The resulting solution was nowstirred into 312.5 grams of tetraethylorthosilicate. This solution waskept stirring for one hour until the hydrolysis reaction was complete.The resulting hydrogel was now transferred to a one-liter polypropylenebottle.

The polypropylene bottle was loosely capped and placed into a steambox(100° C.) to promote the crystallization of the zeolite. The nextmorning the bottle was removed from the steambox and the bottle cap wasnow closed tightly. The bottle was shaken vigorously, then replaced intothe steambox. The reaction mixture for the initial hydrogel formed forthesynthesis of the indium-containing ZSM-20 can be described by thefollowingset of mole ratios:

    ______________________________________                                               SiO.sub.2 /In.sub.2 O.sub.3                                                            150                                                                  H.sub.2 O/SiO.sub.2                                                                    10                                                                   OH.sup.- /SiO.sub.2                                                                    0.9                                                                  Na.sup.+ /SiO.sub.2                                                                    0.09                                                                 TEA.sup.+ /SiO.sub.2                                                                   0.93                                                                 SiO.sub.2 /Al.sub.2 O.sub.3                                                            30                                                            ______________________________________                                    

Samples of the solid product were removed daily from the polypropylenebottle for X-ray diffraction (XRD) analysis to determine the productcrystallinity. XRD analysis showed that the ZSM-20 crystallization wascomplete in 14 days. The polypropylene bottle was removed from thesteambox, and the solid product was filtered on a Buchner funnel. Afterfiltration, the product zeolite was boiled in de-ionized water and againfiltered and dried under an infrared heat lamp. After drying, a sampleof the product was submitted for XRD and chemical analysis. XRD analysisshowed the product to be zeolite ZSM-20. The chemical analysis for theindium-containing ZSM-20 was:

    ______________________________________                                        Weight Percent                                                                C      N      Na      In    SiO.sub.2                                                                            Al.sub.2 O.sub.3                                                                     Ash                                 ______________________________________                                        10.0   1.2    3.0     3.08  58.5   11.4   75.1                                which gives:                                                                   ##STR10##        Moles per Mole In.sub.2 O.sub.3 N.sub.2 O:Na.sub.2                            O:Al.sub.2 O.sub.3 :SiO.sub.2                               ______________________________________                                        9.7               3.19:4.86:8.33:72.7                                         ______________________________________                                    

Example 6

Indium-containing zeolite Beta was synthesized in the following manner:

5.95 grams of sodium aluminate and 4.68 grams of indium nitrate weredissolved in 85.14 grams of de-ionized water. After the salts dissolved,105.0 ml of 3.1N TEAOH was added to the solution. The resulting solutionwas transferred to a 300 ml stainless-steel autoclave.

Now 46.67 grams of solid silica gel (SPEX Industries) was pored into theautoclave, the autoclave was sealed and stirring and heating begunimmediately. The reaction was carried out at 160° C. with stirring (400rpm).

The initial reaction mixture for the synthesis of indium-containingzeoliteBeta can be described by the mole ratios:

    ______________________________________                                               SiO.sub.2 /In.sub.2 O.sub.3                                                            90                                                                   H.sub.2 O/SiO.sub.2                                                                    12                                                                   OH.sup.- /SiO.sub.2                                                                    0.40                                                                 Na.sup.+ /SiO.sub.2                                                                    0.09                                                                 TEA.sup.+ /SiO.sub.2                                                                   0.46                                                                 SiO.sub.2 /Al.sub.2 O.sub.3                                                            30                                                            ______________________________________                                    

After 4 days the autoclave was quenched in a water plus ice bath toterminate the reaction. The solid product was filtered, boiled in waterand again filtered. XRD analysis showed the crystalline product to bezeolite Beta. Chemical analysis of the indium-containing zeolite Betaproduct gave the following results:

    ______________________________________                                        Weight Percent                                                                C      N      Na      In    SiO.sub.2                                                                            Al.sub.2 O.sub.3                                                                     Ash                                 ______________________________________                                        10.84  1.71   1.4     2.5   69.8   4.2    79.92                               which gives:                                                                   ##STR11##        Moles per Mole In.sub.2 O.sub.3 N.sub.2 O:Na.sub.2                            O:Al.sub.2 O.sub.3 :SiO.sub.2                               ______________________________________                                        7.4               5.61:2.79:3.78:62.8                                         ______________________________________                                    

Example 7

Indium-containing crystalline aluminophosphate molecular sieve ALPO-5was synthesized as follows:

23.1 grams of concentrated phosphoric acid (86.3% H₃ PO₄) was dilutedwith 30.0 grams of de-ionized water. Now 10.0 grams of Kaiser aluminawas stirred into this acid solution and the mixture was digested for 45minutes at 90° C. with continuous stirring. After the digestion period asolution containing 1.18 grams of indium nitrate dissolved in 41.0 gramsof de-ionized water was stirred into the gel. Finally, 37.0 grams of 40%wt. TEAOH solution was stirred into the gel andstirring continued untila uniform gel was produced. This gel was now transferred to a 300 mlstainless-steel autoclave. The resulting reaction mixture hydrogel canbe described by the following mole ratios:

    ______________________________________                                               P.sub.2 O.sub.5 /Al.sub.2 O.sub.3                                                      1.0                                                                  H.sub.2 O/Al.sub.2 O.sub.3                                                             59                                                                   H.sup.+ /Al.sub.2 O.sub.3                                                              7.2                                                                  In.sub.2 O.sub.3 /Al.sub.2 O.sub.3                                                     0.02                                                                 TEA.sup.+ /Al.sub.2 O.sub.3                                                            1.0                                                           ______________________________________                                    

The autoclave was sealed and heated and stirring begun immediately. Thereaction was carried out at 160° C. with stirring (400 rpm).

After 4 days the autoclave was quenched in a water+ice bath to terminatethe crystallization. The solid product was filtered, boiled in water andfiltered again. After drying the product, XRD analysis showed thematerialto be crystalline aluminophosphate designated by Union Carbideas ALPO-5. Chemical analysis of the indium-containing ALPO-5 gave:

    ______________________________________                                        Weight Percent                                                                C      N      Na      P     Al     In     Ash                                 ______________________________________                                        6.66   0.84   0.48    21.05 16.01  1.44   89.45                               which gives:                                                                   ##STR12##        Moles per Mole In.sub.2 O.sub.3 N.sub.2 O:Na.sub.2                            :P.sub.2 O.sub.5 :Al.sub.2 O.sub.3                          ______________________________________                                        9.2               4.78:1.66:54.2:47.3                                         ______________________________________                                    

Example 8

Indium-containing crystalline silicoaluminophosphate molecular sieveSAPO-5was synthesized in a manner analogous to Example 7:

46.2 grams of concentrated phosphoric acid (86.3% H₃ PO₄) was firstdiluted with 60.0 grams of de-ionized water then 20.0 grams of Kaiseralumina was added to the solution. This mixture was now digested ona hotplate at 90° C. for 45 minutes, with continuous stirring. At the end ofthe digestion period, a solution containing 2.36 grams of indium nitratedissolved in 82.0 grams of de-ionized water was stirred into the gel.Next 74.0 grams of 40% wt TEAOH solution was stirred into the gel. Thismixture was now stirred at room temperature until a uniform hydrogel wasproduced. The resulting hydrogel was transferred to a one-literstainless-steel autoclave. Before sealing the autoclave, 2.04 grams oftetraethylorthosilicate was transferred to the autoclave. The autoclavewas then sealed and heating and stirring was begun immediately. Theresulting reaction mixture can be described by the following moleratios:

    ______________________________________                                               P.sub.2 O.sub.5 /Al.sub.2 O.sub.3                                                      1.0                                                                  H.sub.2 O/Al.sub.2 O.sub.3                                                             59                                                                   H.sup.+ /Al.sub.2 O.sub.3                                                              7.2                                                                  In.sub.2 O.sub.3 /Al.sub.2 O.sub.3                                                     0.02                                                                 SiO.sub.2 /Al.sub.2 O.sub.3                                                            0.10                                                                 TEA.sup.+ /Al.sub.2 O.sub.3                                                            1.0                                                           ______________________________________                                    

The crystallization of the indium-containing SAPO was carried out at150° C. with stirring (400 rpm).

At the end of 4 days the autoclave was quenched in a water+ice bath toterminate the crystallization. The solid product was filtered, boiled inwater, and re-filtered. After drying under a heat lamp, XRD analysisshowed that the reflection lines for the product corresponded tosilicoaluminophosphate SAPO-5, a Union Carbide designation for thismaterial.

Chemical analysis of the indium-containing SAPO-5 gave:

    ______________________________________                                        Weight Percent                                                                C     N      Na       P    Al     In   Si     Ash                             ______________________________________                                        6.32  0.60   0.48     19.88                                                                              15.71  1.45 0.66   85.00                           which gave                                                                     ##STR13##     Moles per Mole In.sub.2 O.sub.3 N.sub.2 O:Na.sub.2                            O:P.sub.2 O.sub.5 :Al.sub.2 O.sub.3 :SiO.sub.2                 ______________________________________                                        12.3           3.39:1.65:50.8:46.1:3.7                                        ______________________________________                                    

Example 9

Platinum incorporation into the indium-containing silicate of ZSM-5structure was carried out by direct addition of a platinum compound tothezeolite synthesis reaction mixture as follows:

A solution was prepared by dissolving 2.00 grams of indium nitrate and13.07 grams of NaOH pellets in 710.28 grams of de-ionized water. Afterthesolids dissolved, 26.6 grams of tetrapropylammonium bromide (TPABr)was dissolved in the solution. Finally 1.29 grams of platinumtetraaminenitrate [Pt(NH₃)₄ (NO₃)₂ ] was dissolved in the solution, andthe solution was transferred to a one-liter stainless-steel autoclave.Before sealing the autoclave, 66.67 grams of commercial silica gel (SPEXIndustries) was poured into the autoclave. Theautoclave was then sealedand heating and stirring was begun immediately. The reaction mixturehydrogel can be described by the following mole ratios:

    ______________________________________                                               SiO.sub.2 /In.sub.2 O.sub.3                                                            300                                                                  H.sub.2 O/SiO.sub.2                                                                    40                                                                   OH.sup.- /SiO.sub.2                                                                    0.30                                                                 Na.sup.+ /SiO.sub.2                                                                    0.33                                                                 TPA.sup.+ /SiO.sub.2                                                                   0.10                                                                 SiO.sub.2 /Pt                                                                          300                                                           ______________________________________                                    

The crystallization was carried out at 170° C. with stirring (400 rpm).

After 4 days the autoclave was quenched in a water+ice bath to terminatethe crystallization. In the usual manner the solid product was filtered,boiled in water, and finally filtered again before drying under a heatlamp. XRD analysis of the solid product showed the material to becrystalline zeolite ZSM-5.

Chemical analysis of the indium-containing ZSM-5 product gave:

    ______________________________________                                        Weight Percent                                                                C     N      Na       In  Pt     SiO.sub.2                                                                          Al.sub.2 O.sub.3                                                                      Ash                             ______________________________________                                        8.27  0.74   1.3      1.1 0.52   82.7 0.0265  85.05                           which gave:                                                                    ##STR14##     Moles per Mole In.sub.2 O.sub.3 N.sub.2 O:Na.sub.2                            O:Al.sub.2 O.sub.3 :SiO.sub.2 :Pt                              ______________________________________                                        13.1           5.52:5.90:0.05:288:0.55                                        ______________________________________                                    

Example 10

A boron-containing zeolite beta was synthesized and then calcined toremovethe organic template, by heating first in N₂ 25°-530° at10/min andheld 6 hrs. then in air in N₂ 25°-530° at 10/min. and held 6 hours.

25 g of the calcined zeolite was ion-exchanged with 750 mg Pt(NH₃)₄ Cl₂in 400 ml H₂ O at room temperature overnight. The dried material wasthen calcined in flowing oxygen (100 cc/min.) 25°-350° at 1/2°/min. andheld 1 hour.

10 g of the calcined Pt-containing zeolite was then treated with 0.9 gIn(NO₃)₃ H₂ O in 200 ml H₂ O at room temperature overnight.

The zeolite was filtered and washed.

The In-containing Pt/zeolite was added to 150 ml H₂ O and titrated to pH9.0 with 0.5 MCsOH (11/2 hrs). The material was filtered, washed, anddried. The final product contained 0.76% Pt, 11% Cs, 1.1% In, and 0.08%B.

Example 11

The synthesis of a binary oxide zeolite having the structure of ZSM-5was carried out in the two-phase system as in Ser. No. 878,555 filedJune 26, 1986. The aqueous phase of the two-phase system comprised 2.8 gIn(NO₃)₃ xH₂ O dissolved in 35 g water to which was added 63 g TPAOH(40% in H₂ O). Constituting the organic phase was 77.0 g Si(OCH₃)₄dissolved in 35 g of l-hexanol. The mixture was nucleated at 180° C. for24 hours and crystallized at 200° C. for 144 hours. The final productwas filtered and washed. The X-ray diffraction pattern of the driedmaterial proved it to be well-crystallized ZSM-5.

The sample was ammonium-exchanged (1M NH₄ Cl, twice, 60° C., 20ml/gzeolite) and calcined. The chemical composition of the ash of a 1000° C.calcined sample was 79.3 wt. % SiO₂ and 1.5 wt. % In₂ O₃. The ashresidue also contained a small quantity, i.e. 85ppm, of aluminum.

Temperature-programmed desorption of ammonia indicated an exchangecapacityof 0.09 meq/g for the product of this example. The Si/In ratiofrom TPAD was 190.5. The sample had an Alpha Value of 1.0.

The particle size of the product from this example was about 0.2microns. The particles were made of pure single crystals with almostcubic appearance.

Example 12

The synthesis of Example 11 was repeated, except that the mixturecontained3.6 g In(NO₃)₃.xH₂ O in the aqueous phase. The product materialwas filtered and dried. It had the same characteristic ZSM-5 X-ray linesas the product of Example 11. The material was calcined andammonium-exchanged as described in Example 11. The chemical compositionofthe ash of a 1000° C. calcined sample was 78.2 wt. % SiO₂ and 3.1 wt.% In₂ O₃. The ash residue also contained a small quantity, i.e. 180 ppm,of aluminum.

Temperature-programmed desorption of ammonia indicated an exchangecapacityof 0.21 meq/g for the product of this example. The Si/In ratiofrom TPAD was 77.9. The sample had an Alpha Value of 2.5.

The particle size of the product from this example was about 0.2microns. The particles were made of crystals with almost cubicappearance. There were no impurities present.

Examples 13-17

The synthesis of Example 11 was repeated, except that the mixturescontained varying amounts of In(NO₃)₃.xH₂ O. Five preparations weremade, with the following compositions:

    ______________________________________                                        Example    13        14     15     16   17                                    ______________________________________                                        Aqueous Phase (g)                                                             H.sub.2 O  40.0      40.0   35.0   40.0 40.0                                  In(NO.sub.3).sub.3 xH.sub.2 O                                                            0.9       7.2    1.8    1.8  3.6                                   TPAOH, 40% 63.0      63.0   63.0   63.0 63.0                                  Organic Phase (g)                                                             1-Hexanol  60.0      60.0   35.0   60.0 60.0                                  Si(OCH.sub.3).sub.4                                                                      77.0      77.0   77.0   77.0 77.0                                  ______________________________________                                    

The product materials were filtered and dried. They had the samecharacteristic X-ray lines as ZSM-5. The materials were calcined andammonium-exchanged as in Example 11. Their properties were as follows:

    ______________________________________                                        Example      13      14      15    16    17                                   ______________________________________                                        SiO.sub.2, wt. %                                                                           84.0    77.5    80.5  76.7  82.5                                 In.sub.2 O.sub.3, wt. %                                                                    0.67    5.1     1.58  1.31  2.92                                 Al, ppm      105     65      130   85    60                                   Exchange Capacity,                                                            meq/g        0.09    0.17    0.17  0.12  0.21                                 Si/In (from TPAD)                                                                          193     99      95    138   77                                   Alpha Value  1.5     1.6     1.0   1.0   n.d.                                 Particle size                                                                              2000A   1 micr  2000A 2000A 2000A                                ______________________________________                                    

What is claimed is:
 1. A non-acidic catalyst consisting of 0.1 to 20weight percent, based on the total weight of the catalyst, of ahydrogenation/dehydrogenation metal; and the remainder being anon-acidic crystalline microporous material, containing 0.05 to 20weight percent, of indium, said weight percent of indium based on thecatalyst;wherein the non-acidic catalyst is substantially free of bothcracking activity and hydrogenolysis activity under conditions ofdehydrogenation or dehydrocyclization; wherein the material exhibits theX-ray diffraction pattern of one of those selected from the groupconsisting of ZSM-5, ZSM-11, ZSM-12, ZSM-23, ZSM-35, ZSM-48, ZSM-50,ZSM-20, and zeolite beta.
 2. The catalyst of claim 1, wherein thehydrogenation/dehydrogenation metal is at least one metal selected fromthe group consisting of a Group VIII metal, chromium and vanadium. 3.The catalyst of claim 1, wherein the hydrogenation/dehydrogenation metalis a platinum group metal.
 4. The catalyst of claim 1, wherein thehydrogenation/dehydrogenation metal is platinum.
 5. The catalyst ofclaim 1, wherein the crystalline microporous material contains aluminumin an amount less than 0.1 weight percent, based on the material.
 6. Thecatalyst of claim 1, wherein the material exhibits the X-ray diffractionpattern of ZSM-5.
 7. The catalyst of claim 1, wherein the materialexhibits the X-ray diffraction pattern of ZSM-11.
 8. The catalyst ofclaim 1, wherein the material exhibits the X-ray diffraction pattern ofZSM-12.
 9. The catalyst of claim 1, wherein the material exhibits theX-ray diffraction pattern of ZSM-48.
 10. The catalyst of claim 1, whichwhen added to water exhibits a pH of at least 7.5.
 11. The catalyst ofclaim 1, which also contains at least one Group I or Group II metal. 12.The catalyst of claim 11, wherein said at least one metal is cesium orsodium.
 13. A catalyst comprising 0.1 to 20 weight percent platinum; andZSM-5, contains less than about 0.1 weight percent aluminum andcontaining indium in an amount from 0.05 to 20 weight percent.
 14. Thecatalyst of claim 1, wherein said platinum is intrazeolitic.